Renal Regional Oxygen Saturation Research Articles

Renal Regional Oxygen Saturation and Acute Kidney Injury in Neonates with Perinatal Asphyxia.

Neonates with moderate-to-severe perinatal asphyxia often develop acute kidney injury (AKI). Additionally, therapeutic hypothermia (TH) can affect renal blood flow. This study aimed to evaluate the association between renal regional oxygen saturation (rSrO2) during TH and AKI in neonates with moderate and severe perinatal asphyxia. This retrospective longitudinal study included neonates with moderate-to-severe asphyxia who required TH. The primary outcome was the occurrence of AKI, classified as a rate of decrease in creatinine levels of <33% at 72 hours of TH. rSrO2 was continuously monitored by near-infrared spectroscopy during the hypothermia and rewarming phases. Data analysis involved dividing the average rSrO2 levels into 12-hour periods. We analyzed the association between AKI and rSrO2 levels using univariate and multivariate logistic regression models. Furthermore, we assessed the predictive capacity of rSrO2 for AKI by analyzing the area under the receiver operating characteristic curve. Ninety-one patients were included in the study. On average, patients with AKI exhibit lower rSrO2 levels during TH. Specifically, rSrO2 levels within the first 12 hours and between 25 and 72 hours of TH demonstrated the highest predictive capability for AKI. Multivariate logistic regression analysis revealed that rSrO2 levels within the initial 12 hours (adjusted odds ratio [aOR] = 1.11, 95% confidence interval [CI]: 1.01-1.21) and between 61 and 72 hours (aOR = 0.85, 95% CI: 0.78-0.92) were significantly associated with AKI. An increase in rSrO2 during the first 12 hours of TH and lower rSrO2 levels between 61 and 72 hours of treatment were associated with the development of AKI in asphyxiated neonates undergoing TH. · Neonates with asphyxia often develop AKI.. · Renal saturations are affected by hypothermia and asphyxia. · Patients with AKI initially show higher rSrO2, then lower rSrO2.. · Monitoring rSrO2 identifies early AKI..

Evaluation of renal oxygenation by near-infrared spectroscopy during endoscopic injection of bulking agents in children with vesicoureteral reflux.

Near infrared spectroscopy (NIRS) is the measuring of regional tissue oxygenation (rSO2) by interpreting oxyhemoglobin and deoxyhemoglobin signals that come back by transmitting near infrared light to tissues. The effect of endourological interventions on renal perfusion in children is largely unknown. To evaluate the effects of endoscopic injection of bulking agents (EIBA) for vesicoureteral reflux (VUR) on renal oxygenation (RO) using renal NIRS monitoring, which shows renal perfusion and oxygenation changes. Case-control study. Group I had bilateral inguinal surgery, Group II cystoscopy, and Group III, EIBA for VUR with 30 patients in each group. During the operation, vital signs, peripheral oxygen saturation, end-tidal carbon dioxide, and renal regional oxygen saturation index (rSO2) values by bilateral renal NIRS monitoring were recorded. NIRS values before induction (T0) to postoperative (Tend) were determined. A 20% or more reduction in renal rSO2 (%20↓rSO2) was considered significant. Group III was also evaluated as subgroup III-A (not having "%20↓rSO2") and subgroup III-B ("%20↓rSO2"). The rSO2 decrease was observed in the first 5min for both sides in group III. The most significant drop was at T30 for the right kidney and a significant decrease in rSO2, 20% or more, was observed in 6 renal units of 4 patients having higher SFU grading and renal scar in group III. EIBA may transitionally impair renal oxygenation. Higher SFU grading and renal scar may increase the risk of renal hypoxia during EIBA.

Retroperitoneoscopic Surgery in Children Does Not Cause Pathological Desaturation in Cerebral/Renal Oxygenation on Near-Infrared Spectroscopy Compared with Laparoscopic and Thoracoscopic Surgery.

Introduction: Cerebral and renal regional oxygen saturation (C-rSO2 and R-rSO2, respectively) were monitored using near-infrared spectroscopy in pediatric patients (range: 0.3-14.3 years) during minimally invasive surgery (MIS) taking at least 3 hours performed by laparoscopy (Lap), thoracoscopy (Tho), or retroperitoneoscopy (Ret) from January 2019 to December 2021. Materials and Methods: Criteria compared were operative time, preoperative/intraoperative hemoglobin, blood loss, mean arterial pressure, arterial partial pressure of carbon dioxide (PaCO2), peripheral oxygen saturation (SpO2), C-rSO2, and R-rSO2. Pathological desaturation (PD) was defined as >20% decrease from baseline, and statistical significance as P < .05. Results: Subjects (n = 79) were similar for gender, age, and body mass index. MIS procedures were: Lap = 45, Tho = 20, Ret = 14; one Lap case required conversion for severe adhesions, not PD. Intraoperative PaCO2 (mmHg) was significantly higher in Tho (maximum: 59.5 ± 17.0, minimum: 39.9 ± 7.5) versus Lap (maximum: 39.9 ± 5.1, minimum: 34.6 ± 3.9) and Ret (maximum: 37.8 ± 4.2, minimum: 35.0 ± 3.3); P < .0001 (maximum), P = .0013 (minimum). Minimum intraoperative SpO2 was significantly lower in Tho (P < .0001). Mean operative times were significantly shorter in Tho (259 ± 114 minutes) versus Lap (433 ± 154 minutes) and Ret (342 ± 100 minutes); P < .0001, respectively. PD was absent during Ret (C-rSO2: 0/14 = 0% and R-rSO2: 0/14 = 0%). Differences in PD for Lap (C-rSO2: 7/45 = 15.6% and R-rSO2: 10/45 = 22.2%) and Tho (C-rSO2: 9/20 = 45.0%, and R-rSO2: 7/20 = 35.0%) were significant; P = .0028 for C-rSO2 and P = .0497 for R-rSO2. Hemoglobin and blood loss were similar. Conclusions: PD was absent during Ret, despite longer operative times. If Ret is indicated for a procedure, neurodevelopmental sequelae of MIS could be minimized.

Impact of intrauterine growth restriction on cerebral and renal oxygenation and perfusion during the first 3 days after birth

Intrauterine growth restriction (IUGR) is associated with a higher incidence of perinatal complications as well as cardiovascular and renal diseases later on. A better insight into the disease mechanisms underlying these sequalae is important in order to identify which IUGR infants are at a higher risk and find strategies to improve their outcome. In this prospective case–control study we examined whether IUGR had any effect on renal and cerebral perfusion and oxygen saturation in term neonates. We integrated near-infrared spectroscopy (NIRS), echocardiographic, Doppler and renal function data of 105 IUGR infants and 105 age/gender-matched controls. Cerebral and renal regional oxygen saturation values were measured by NIRS during the first 12 h after birth. Echocardiography alongside Doppler assessment of renal and anterior cerebral arteries were performed at 6, 24, 48 and 72 h of age. Glomerular and tubular functions were also assessed. We found a left ventricular dysfunction together with a higher cerebral oxygen saturation and perfusion values in the IUGR group. IUGR term infants showed a higher renal oxygen saturation and a reduced oxygen extraction together with a subclinical renal damage, as indicated by higher values of urinary neutrophil gelatinase-associated lipocalin and microalbumin. These data suggest that some of the haemodynamic changes present in growth-restricted foetuses may persist postnatally. The increased cerebral oxygenation may suggest an impaired transition to normal autoregulation as a consequence of intra-uterine chronic hypoxia. The higher renal oxygenation may reflect a reduced renal oxygen consumption due to a subclinical kidney damage.

Regional oxygen saturation and acute kidney injury in premature infants

Decreased renal blood flow plays a vital role in the etiology of acute kidney injury (AKI). In this study, we aim to investigate the role of renal regional oxygen saturation (rSO2 ) reductions in predicting AKI in the first 24h of life. One hundred premature babies with a gestational age of ≤32weeks were included. Renal and cerebral rSO2 s were monitored for 24 h by near-infrared spectroscopy. Infants were followed up for the first 7days for the diagnosis of AKI. Infants' median gestational age was 29 (23-32) weeks, and their birthweight was 1,192±355g. It was found that the renal rSO2 values were lower in the first 24h of life in patients who developed AKI, and this decrease was statistically significant in the first 6h of life. The low renal rSO2 values in the early hours of life in premature babies may have a role in predicting AKI.

Evaluation of renal oxygenization in laparoscopic pediatric surgery by near infrared spectroscopy.

Increased intraabdominal pressure IAPmay reduce renal blood flow (RBF). The study aims to evaluate the pneumoperitoneum effect on RBF by comparing renal regional oxygen saturation index (rSrO2) measured by near-infrared spectroscopy (NIRS) in pediatric patients having laparotomy and laparoscopy. Of 58 patients having laparoscopy and laparotomy, 18 were excluded due to renal pathologies, combined open surgical procedures, and administration of inotropic drugs. Hemodynamic parameters and rSrO2 were recorded in laparoscopy (n = 20) and laparotomy (n = 20) groups before induction and with 5min intervals up to 60min and at post-extubation. Decrease in right renal rSrO2 at 45th and 60th min and 30th, 45th and 60th min in left were significant in the laparoscopy group compared to laparotomy group. In the laparoscopy group, reductions at T25, T30, T45, and T60 were significant in both renal rSrO2. Renal rSO2 increased to normal with desufflation. IAP with pneumoperitoneum may lead to renal hypoxia in children. Renal rSO2 returns to normal with desufflation. Renal NIRS monitorization might be needed in patients with renal parenchymal and vascular pathologies, solitary kidney, and multiorgan pathologies that may affect renal oxygenation.

Correlation of intraoperative renal near infrared spectroscopy with the development of acute kidney injury in adult patients undergoing cardiac surgery using cardiopulmonary bypass

Introduction: The present study aimed to correlate renal oximetry near-infrared spectroscopy (NIRS) values with conventional non-invasive biomarkers for the early detection of acute kidney injury (AKI) in adult patients undergoing cardiac surgery using cardiopulmonary bypass (CPB). Accordingly, renal NIRS can be employed as a trending device for the prevention of AKI development. Materials and methods: After institutional ethical committee approval, a number of 132 adult patients undergoing cardiac surgery with CPB were selected by consecutive consenting sampling method. Emergency surgery and patients with preexistent renal insufficiency were excluded. NIRS sensor was applied on either the right or the left side of the spine at the lower border of L-1 before starting the induction. A renal regional oxygen saturation (rSO2) score was calculated after recording the renal oximetry values intra- and postoperatively. Urine output and serum creatinine were measured at 24, 48, and 72 hours postoperatively. Results: Out of 132 patients, 22 cases (16.66 %) developed AKI according to Acute Kidney Injury Network (Akin) criteria± Risk, Injury, Failure, Loss, and End-stage kidney disease (RIFLE) classification. Among these AKI patients, three cases required dialysis, and one of these three patients died on the 21st day postsurgery. Renal rSO2 scores in the AKI group were measured at 535 and 912 minutes %, in comparison to 162 and 184 minutes % reported in the non-AKI group which was statistically significant (P< 0.05). Conclusion: As evidenced by the obtained results, there is a correlation between intraoperatively measured renal NIRS readings and the occurrence of AKI following adult cardiac surgery using CPB.

Acute Kidney Injury and Renal Regional Oxygen Saturation During Pediatric Liver Transplantation.

BackgroundKidney injury is a complication among children undergoing liver transplantation (pLTx). Cystatin C serum concentration seems to be superior to creatinine-based determination of kidney injury in adults and children. Near-infrared spectroscopy (NIRS) technology provides non-invasive and real-time measurement of renal tissue oxygenation. Here, we compared renal tissue oximetry (rSrO2) with conventional diagnostic criteria cystatin C and creatinine concentration in children undergoing pLTx.Material/MethodsrSrO2 was measured intraoperatively in children undergoing pLTx over the left kidney, and was statistically compared with pre- and postoperative serum creatinine and cystatin C concentrations.ResultsrSrO2 was affected by hemoglobin concentration, bilirubin concentration, and FiO2. Statistical analysis demonstrated that rSrO2 was significantly reduced in children with preoperative pathologic increased cystatin C concentrations compared to children without (63.7±4.3 vs. 53.4±4.9, p<0.05). We did not detect a significant difference in rSrO2 between children who developed postoperative renal impairment, either determined by increased postoperative cystatin C concentration, creatinine concentration, or the pRIFLE criteria. Intraoperative increase or decrease in rSrO2 did not predict the development of postoperative kidney injury.ConclusionsIn children with liver failure undergoing pLTx, a preoperative decrease in rSrO2 indicates compromised renal function. However, intraoperative rSrO2 is not predictive of postoperative kidney injury.

Changes in cerebral and renal oxygenation during laparoscopic pyloromyotomy

Although a laparoscopic approach may be preferred over open procedures for abdominal surgery, there are limited data on the effect of laparoscopic procedures on cerebral and renal oxygenation in neonates and young infants. Here, we evaluated the effect in neonates and infants. In this two-center prospective observational study, we evaluated changes in cerebral and renal regional oxygen saturation (rSO2) in infants during laparoscopic pyloromyotomy. Intraoperative hemodynamic and respiratory parameters and rSO2 were recorded. For the primary outcome, these parameters were compared at incision and at the end of pneumoperitoneum. The study cohort included 25 infants with a mean age of 40 ± 10days and weight of 4.0 ± 0.6kg. IAP at the beginning of laparoscopy was 10 ± 2mmHg (range 7-15mmHg). Although both cerebral and renal rSO2 decreased from incision compared to the end of laparoscopy, the decrease reached statistical significance only for cerebral rSO2 (81 ± 12 to 76 ± 16, p = 0.033). Similarly, the increase in fractional tissue oxygen extraction (FTOE) was only statistically significant for cerebral FTOE (0.18 ± 0.12 to 0.23 ± 0.16, p = 0.037). No change in hemodynamic or respiratory parameters was found. Although there was a decrease in cerebral rSO2 and increase in cerebral FTOE during pneumoperitoneum, the values did not decrease below those noted before anesthetic induction.

Association of Intraoperative Renal Regional Oxygen Saturation and Acute Kidney Injury

Association of Intraoperative Renal Regional Oxygen Saturation and Acute Kidney Injury

Low Renal Oxygen Saturation at Near-Infrared Spectroscopy on the First Day of Life Is Associated with Developing Acute Kidney Injury in Very Preterm Infants

Background: Acute kidney injury (AKI) is a frequent complication in preterm infants, and the identification of early markers of renal hypoperfusion is a chief challenge in neonatal intensive care units. Objectives: To describe the association between early markers of cardiovascular function and renal perfusion with AKI occurrence in a cohort of preterm infants < 32 weeks’ gestation. Methods: 128 infants were prospectively included from birth to discharge. During the first day of life, we assessed cardiovascular function, systemic and organ blood flow by Doppler ultrasound, and monitored cerebral and renal regional oxygen saturation (rSO₂) using near-infrared spectroscopy (NIRS). These measures were analyzed in relation to developing AKI and serum creatinine (SCr) peak from day 2 to 7 of life. Results: 12 of 128 infants presented with AKI (9.4%). SCr peak was 155.3 ± 30.2 µmol/L in infants with AKI versus 82.0 ± 16.5 in non-AKI infants (p < 0.001). Among all measures of cardiovascular function and renal perfusion, low mean cerebral and renal rSO₂ during the first day of life and a low resistive index at renal artery Doppler were significantly associated with developing AKI. After adjustment for possible confounding factors, low renal rSO₂ on the first day of life remained associated with a high SCr peak from day 2 to 7 of life. Conclusion: Low renal rSO₂ values during the first day of life correlate with developing AKI in preterm infants < 32 weeks’ gestation. NIRS monitoring of renal function during adaptation seems promising, and its very early use after birth to detect kidney hemodynamic dysfunction deserves further investigations.

Cardiac Surgery-Associated Kidney Injury in Children and Renal Oximetry.

Cardiac surgery-associated acute kidney injury is common in children and associates with negative outcomes. Novel interventions to reduce cardiac surgery-associated acute kidney injury require knowledge of its pathophysiology. States of altered perfusion, oxygen delivery, and energy consumption occur during cardiopulmonary bypass and could protect against or contribute to renal cellular injury and recovery. Near-infrared spectroscopy is noninvasive technology for monitoring regional blood flow and tissue oxygenation. This study evaluated the relationship between renal regional oxygen saturation and cardiac surgery-associated acute kidney injury, using near-infrared spectroscopy monitoring before, during, and after cardiopulmonary bypass in children. Prospective cohort study. Single-center, tertiary care pediatric hospital (Stollery Children's Hospital, Edmonton, AB, Canada). Children less than or equal to 10 kg undergoing congenital heart disease repair with cardiopulmonary bypass. Heart transplant, preoperative dialysis, sepsis, extracorporeal life support, congenital renal disease, and preoperative nephrotoxins were exclusions. Renal regional near-infrared spectroscopy monitoring before, during, and after cardiopulmonary bypass. Outcome measure was cardiac surgery-associated acute kidney injury (defined according to Kidney Disease: Improving Global Outcomes criteria). Regional oxygen saturation was measured continuously using near-infrared spectroscopy (INVOS 5100C Cerebral/Somatic Oximeter; Medronic, Troy, MI) from time of anesthesia to time of transfer to intensive care. Cardiac surgery-associated acute kidney injury occurred in 65%. Lower baseline (precardiopulmonary bypass) regional oxygen saturation was associated with decreased risk of cardiac surgery-associated acute kidney injury (p = 0.01); children with baseline regional oxygen saturation in the highest tertile were 7.14 times more likely to get cardiac surgery- associated acute kidney injury (vs lowest tertile). Area under the curve for ability of baseline regional oxygen saturation to predict cardiac surgery-associated acute kidney injury was 0.73 (95% CI, 0.60-0.85). Children with lower baseline glomerular filtration rate had lower mean renal regional oxygen saturation. Findings demonstrate that preoperative oxygen supply/demand balance is an important predictor of cardiac surgery-associated acute kidney injury, suggesting lower preoperative (and intraoperative) renal blood flow may be protective. There is not yet a definite link between remote ischemic preconditioning and prevention of cardiac surgery-associated acute kidney injury; however, renal protective effects of sublethal ischemia should continue to be explored.

Hemodynamic Changes During Rewarming Phase of Whole-Body Hypothermia Therapy in Neonates with Hypoxic-Ischemic Encephalopathy

To delineate the systemic and cerebral hemodynamic response to incremental increases in core temperature during the rewarming phase of therapeutic hypothermia in neonatal hypoxic-ischemic encephalopathy (HIE). Continuous hemodynamic data, including heart rate (HR), mean arterial blood pressure (MBP), cardiac output by electrical velocimetry (COEV), arterial oxygen saturation, and renal (RrSO2) and cerebral (CrSO2) regional tissue oxygen saturation, were collected from 4 hours before the start of rewarming to 1 hour after the completion of rewarming. Serial echocardiography and transcranial Doppler were performed at 3 hours and 1 hour before the start of rewarming (T-3 and T-1; "baseline") and at 2, 4, and 7 hours after the start of rewarming (T+2, T+4, and T+7; "rewarming") to determine Cardiac output by echocardiography (COecho), stroke volume, fractional shortening, and middle cerebral artery (MCA) flow velocity indices. Repeated-measures analysis of variance was used for statistical analysis. Twenty infants with HIE were enrolled (mean gestational age, 38.8 ± 2 weeks; mean birth weight, 3346 ± 695 g). During rewarming, HR, COecho, and COEV increased from baseline to T+7, and MBP decreased. Despite an increase in fractional shortening, stroke volume remained unchanged. RrSO2 increased, and renal fractional oxygen extraction (FOE) decreased. MCA peak systolic flow velocity increased. There were no changes in CrSO2 or cerebral FOE. In neonates with HIE, CO significantly increases throughout rewarming. This is due to an increase in HR rather than stroke volume and is associated with an increase in renal blood flow. The lack of change in cerebral tissue oxygen saturation and extraction, in conjunction with an increase in MCA peak systolic velocity, suggests that cerebral flow metabolism coupling remained intact during rewarming.

Monitoring Cerebral and Renal Oxygenation Status during Neonatal Digestive Surgeries Using Near Infrared Spectroscopy.

Depending on the initial pathology, hypovolemia, intra-abdominal hypertension, and sepsis are often encountered in neonatal digestive surgery. Accurate newborn monitoring during and after surgery is essential to adapt resuscitation protocols. Near infrared spectroscopy (NIRS) is non-invasive and can detect hypoperfusion which indicates a low circulatory blood flow, regardless of the cause. Evaluating changes in cerebral and renal regional oxygen saturation during neonatal digestive surgeries, conducted according to normal practices, with commonly used monitoring parameters. Analyzing retrospectively the inter-relationships between NIRS values and mean arterial pressure (MAP) values as well as pre-ductal SpO2. Prospective, descriptive, monocentric study. All neonates referred for surgery were included. NIRS allows the measurement of cerebral and renal oxygenation fluctuations, as well as calculating difference in intraoperative and postoperative values. Nineteen patients were included. Cerebral regional oxygen saturation (C rSO2) values were stable while renal regional oxygen saturation (R rSO2) values tended to decrease with time during surgery. Indeed, 72% of rSO2 decline episodes occurred after the first 30 min of surgery, without any significant statistical differences for the next 90 min of surgery. After surgery, the lowest average C and R rSO2 values were evidenced during the first 6 h, with 60% of C rSO2 and R rSO2 anomalies occurring in that time frame. There was no significant statistical difference observed in the following 18 h. There was a significant correlation between R rSO2 and SpO2 values (p < 0.01), but not with C rSO2 values. There was no correlation with the MAP either for the C rSO2 values or R rSO2 ones. NIRS is a promising non-invasive bedside tool to monitor cerebral and tissue perfusion, analyzing tissue microcirculation. NIRS has its interest to guide neonatal digestive surgeries (bowel manipulation, viscera reduction) and may represent an early warning for identifying patients requiring resuscitation during or after these surgeries.

Low Plasma Protein Levels at Birth Are Associated with Poor Cardiovascular Adaptation and Serious Adverse Outcome in Infants with Gestational Age

Background: Retrospective studies suggest that early hypoproteinemia has prognostic value for adverse outcome in preemies, but the underlying pathophysiology is unknown. We hypothesized that the prognostic relevance of hypoproteinemia could be related to its association with impaired cardiovascular function and organ perfusion during transition. Objectives: To describe the plasma protein status and the measures of cardiovascular function according to the outcome in infants <32 weeks' gestation. Methods: One hundred and twenty-eight infants were prospectively included from birth to discharge. During the first 24 h of life, we assessed the cardiovascular function and systemic and organ blood flow by Doppler ultrasound, and monitored cerebral and renal regional oxygen saturation (cRSO₂, rRSO₂) using near-infrared spectroscopy. These measures were analyzed in relationship to hypoproteinemia (total plasma protein level <40 g/L at 12 h of life) and severe adverse outcome (death or survival with severe neurological injury). Results: Hypoproteinemia was associated with a higher risk of a severe adverse outcome after adjustment of confounding variables (adjusted OR = 6.8; 95% CI 1.3-34). Compared to normoproteinemic infants and after adjustment for gestational age, hypoproteinemic ones had more significantly: hypotension (7 vs. 13%, p = 0.03), abnormal capillary refilling time (20 vs. 36%, p < 0.001), abnormal renal blood flow (resistive index 0.78 ± 0.11 vs. 0.85 ± 0.09, p = 0.04), lower rRSO₂ (82.9 ± 9.2 vs. 73.6 ± 10.5%, p = 0.04), and lower systemic vascular resistance (0.155 ± 0.058 vs. 0.108 ± 0.037 mm Hg/L/kg; p = 0.04). The cRSO₂ patterns were significantly decreased in infants with severe adverse outcome and independent from protein status. Conclusion: Hypoproteinemia is associated with impaired cardiovascular function. Further studies are required to elucidate the interplay between changes in protein levels, postnatal hemodynamics and clinical outcome.

Effects of sodium bicarbonate correction of metabolic acidosis on regional tissue oxygenation in very low birth weight neonates.

To determine the effects of sodium bicarbonate (NaHCO3) correction of metabolic acidosis on cardiopulmonary, laboratory, and cerebral, renal and splanchnic regional oxygen saturation (rSO2) and fractional tissue oxygen extraction (FTOE) in extremely premature neonates during the first postnatal week. Observational cohort data were collected from 500 to 1250 g neonates who received NaHCO3 'half' corrections (0.3 * Weight (kg) * Base Deficit (mmol l(-1))) for presumed renal losses. Twelve subjects with normal blood pressure and heart rate received 17 NaHCO3 corrections. Mean (±s.d.) gestational age was 27±2 week and birth weight was 912±157 g. NaHCO3 corrections provided a mean (±s.d.) 4.5±1.0 ml kg(-1) fluid bolus, shifted mean (±s.d.) base deficit from 7.6±1.8 to 3.4±2.1 mmol l(-1) (P<0.05), and increased median (±s.d.) pH from 7.23±0.06 to 7.31±0.05 (P<0.05). No significant changes in blood pressure, pulse oximetry, PCO2, lactate, sodium, blood urea nitrogen, creatinine or hematocrit were observed. Cerebral, renal and splanchnic rSO2 (74%, 66% and 44%, respectively, at baseline) and FTOE (0.21, 0.29 and 0.52, respectively, at baseline) were unchanged following NaHCO3 correction. NaHCO3 infusions decreased base deficits and increased pH though produced no discernible effects or benefits on cardiopulmonary parameters including rSO2 and FTOE. These findings warrant further prospective evaluation in larger populations with more significant metabolic acidosis to determine the utility of tissue oxygenation monitoring in differentiating metabolic acidosis due to oxygen delivery/consumption imbalance versus renal bicarbonate losses.

Cerebral, renal and mesenteric regional oxygen saturation of term infants during transition

ObjectiveTo measure cerebral regional oxygen saturation (CrSO2), renal regional oxygenation saturation (RrSO2) and mesenteric tissue regional oxygen saturation (MrSO2) during immediate transition and continuously for the first 9hours of age. Fractional tissue oxygen extraction of the brain (CtFOE), kidneys (RtFOE), splanchnic tissue (MtFOE) were also assessed. Study designProspective, observational study of 61 term infants, delivered by elective caesarean section. Using near-infrared spectroscopy, changes in CrSO2, RrSO2, MrSO2 and changes in CtFOE, RtFOE and MtFOE were measured all through the first 9hours of life. All the episodes of feeding during this period were recorded. ResultsMean CrSO2 increased quickly to 7minutes, with no further changes. On the other hand, mean RrSO2 and mean MrSO2 increased for 10minutes and thereafter they remained on their newly reached level. RrSO2 and MrSO2 were significantly lower at 3-4-5-6-7minutes of life compared to the CrSO2 (p<0.05). RtFOE and MtFOE were significantly higher at 3-4-5-6-7minutes of life compared to the CtFOE (p<0.05). During feeding, CrSO2, RrSO2 and MrSO2 did not significantly change. ConclusionsDuring early adaptive period, oxygen delivery is preserved to ‘vital’ organs, like brain, at the expense of kidneys and splanchnic tissue. Term infants can provide for the increasing metabolic activity of the intestinal tract during feeding periods without compromising oxygenation.

Intraoperative Renal Regional Oxygen Desaturation Can Be a Predictor for Acute Kidney Injury after Cardiac Surgery

To evaluate the usefulness of renal regional oxygen saturation (renal rSO2) in predicting the risk of acute kidney injury (AKI) after cardiac surgery. A prospective observational study. Tertiary care university hospital. One hundred patients undergoing cardiac surgery. Renal rSO2 was monitored continuously by near-infrared spectroscopy (NIRS) throughout the anesthetic period. Postoperative AKI was defined using the Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria. Of 95 patients who were included in the final analysis, 34 patients developed AKI after surgery. Recorded renal rSO2 data were used to calculate the total duration of the time when renal rSO2 was below the threshold values of 70%, 65%, 60%, 55%, and 50%. The total periods when the renal rSO2 level was below each of the threshold values were significantly longer in patients with AKI than in those without AKI (p = 0.001 or p<0.001). Receiver operating characteristic (ROC) curve analysis was used to evaluate the predictive power of renal rSO2 for AKI. The ROC curve analysis showed that renal rSO2 could predict the risk of AKI with statistical significance and that a renal rSO2<55% had the best performance (area under the curve-ROC, 0.777; 95% CI, 0.669-0.885; p<0.001). Multivariate logistic regression analysis revealed that AKI significantly correlated with the duration of renal rSO2<55% (p = 0.002) and logistic EuroSCORE (p = 0.007). Intraoperative renal regional oxygen desaturation can be a good predictor of AKI in adult patients undergoing cardiac surgery.

Splanchnic Oxygen Saturation Immediately After Weaning From Cardiopulmonary Bypass Can Predict Early Postoperative Outcomes in Children Undergoing Congenital Heart Surgery

This study compared the abilities of cerebral, renal, and splanchnic regional oxygen saturation (rSO2) immediately after weaning from cardiopulmonary bypass (CPB) to predict early postoperative outcomes for children undergoing congenital heart surgery. The study enrolled 73 children (ages 0.1-72 months) undergoing corrective or palliative cardiac surgery requiring CPB. Laboratory and hemodynamic variables were analyzed at the time of successful weaning from CPB. Using near-infrared spectroscopy, cerebral, renal, and splanchnic rSO2 values were obtained simultaneously. Early postoperative outcome measures included the maximum vasoactive inotropic score (VIS(max)) during the first 36 postoperative hours, the duration of mechanical ventilation, and the postoperative hospital length of stay. In the univariate analysis, cerebral, renal, and splanchnic rSO2 values correlated significantly with early postoperative outcomes. However, splanchnic rSO2 was the only independent factor predicting VIS(max) (β = -0.302, P = 0.021), duration of mechanical ventilation (β = -0.390, P = 0.002), and postoperative hospital length of stay (β = -0.340, P = 0.001) by multivariate analyses. Splanchnic rSO2 had a larger receiver operating characteristic area under the curve (AUC) for determining high VIS(max), prolonged mechanical ventilation, and longer postoperative hospital stay (AUC 0.775, 0.792, and 0.776, respectively) than cerebral (AUC 0.630, 0.638, and 0.632, respectively) and renal (AUC 0.703, 0.716, and 0.715, respectively) rSO2. After weaning from CPB, splanchnic rSO2 may be superior to rSO2 measured from brain and kidney in predicting an increased requirement for vasoactive inotropic support, a prolonged mechanical ventilation, and a longer postoperative hospital stay for children.

Acute Kidney Injury and Renal Regional Oxygen Saturation During Aortic Arch Reconstruction in Infants

Acute kidney injury is a serious postoperative complication following cardiac surgery. The aortic arch repair technique using antegrade selective cerebral perfusion has been used, but it is unclear whether subdiaphragmatic organs such as the kidneys are perfused adequately. The authors compared intraoperative renal regional oxygen saturation using near-infrared spectroscopy between infants with and without postoperative acute kidney injury after undergoing aortic arch reconstruction. Retrospective medical records review. University medical center. Elective cardiac surgical infants. The author reviewed the perioperative clinical records of infants who underwent aortic arch reconstruction surgery using antegrade selective cerebral perfusion. During the operation, prestenotic (right radial or right brachial artery) and poststenotic (femoral or umbilical artery) invasive arterial blood pressure and cerebral and renal regional oxygen saturation were monitored continuously. Development of acute kidney injury within 72 hours of surgery was investigated. A total of 47 patients were enrolled in this study. Postoperative acute kidney injury occurred in 19 patients (40.4%). Intraoperative renal regional oxygen saturation was similar between patients with and without acute kidney injury. Intraoperative prestenotic and poststenotic mean arterial blood pressure and cerebral regional oxygen saturation also were similar between the 2 groups. The intraoperative renal tissue oxygen saturation was not different between the groups with or without postoperative acute kidney injury in infants who underwent aortic arch repair using antegrade selective cerebral perfusion.